Converting alpha-pinene to mixtures of acids



CONVERTING ALPHA-PINENE TO MIXTURES F ACIDS Gordon S. Fisher, Leo A.Goltiblatt, and James S. Stinson,

Lake City, Fla., assignors to the United States of America asrepresented by the Secretary of Agriculture No Drawing. ApplicationNovember 14, 1951, Serial No. 256,357

4 Claims. or. 260-514) (Granted under Title 35, U. s. Code 1952 sec.266) A nonexclusive, irrevocable, royalty-free license in the inventionherein described, for all governmental purposes, throughout the world,with the power to grant sublicenses for such purposes, is hereby grantedto the Government of the United States of America.

This invention relates to the acids which can be derived by oxidizingalpha-pinene until one or more carboxyl groups are formed on thehydrocarbon structure without opening the substituted cyclobutane ring.Such acids will hereinafter be referred to as pinene-derived acids. Moreparticularly, the invention provides: unique and valuable mixtures ofhydrocarbon dicarboxylic pinenederived acids, and mixtures ofketo-substituted monocarboxylic pinene-derived acids; and a process forthe preparation of such mixtures of acids.

The pinene-derived acids consist essentially of acids having thefollowing structural formulas:

The pinic acids,

HOOCCE CHCHQCOOH the pinonic acids,

C (CHM OHSC 0 0\ 01101120 0 OH the pinononic acids CHaCOCE\I CHCOOH andthe norpinic acids 0 (CH3): HOOCO\ CHCOOH C 2 There are a plurality ofsterio isomers having each of the above structural formulas. Althoughthe proportions may vary widely, substantially all of the pinene-derivedacids are produced concurrently when alpha-pinene is oxidized. Thechemical relationship between many ofthe pinenederived acids is so closethat a complete separation of one individual pinene-derived acid is notcommercially feasible by proven large-scale separation processes.

An object of the present invention is the provision of a process forconverting alpha-pinene to the pinenederived acids mixed in suchproportions that a commercially feasible separation procedure, whichisolates groups of acids of like physical and chemical properties,isolates from the mixture produced by said conversion; mixtures ofhydrocarbon dicarboxylic pinene-derived acids predominating in pinic andnorpinic acids, containing minor amounts of other pinene derived acidsconstituting a uniquely valuable mixture of acids; and mixtures ofketo-substituted monocarboxylic pinene-derived acids predominating inpinonic and pinononic acids, connited States fiatent "O taining minoramounts of other pinene-derived acids, and constituting a uniquelyvaluable mixture of acids.

Another object of the present invention is the provision of acommercially feasible process of producing pinenederived acids, whichprocess, by consuming only comparatively low cost reagents and byavoiding the production of possibly explosive materials in a form inwhich they could be explosive, avoids the disadvantages inherent in theprocesses heretofore developed. A further object of the invention is theprovision of an ozonolysis process which can be controlled to producemixtures of the pinene-derived acids predominating in hydrocarbondicarboxylic pinene-derived acids or predominating in ketosubstitutedmonocarboxylic pinene-derived acids. A further object is to providemixtures of acids containing acyl radicals which impart unique andvaluable properties to mixtures of derivatives produced by the acidreactions of the mixtures of acids. Further objects and advantages ofthe invention will be apparent to those skilled in the art.

It has been known for over 50 years that the pinenederived acids couldbe produced by an alkaline potassium permanganate oxidation. However, asit is well recognized, a large-scale production of a chemical materialby a permanganate oxidation process is generally far too expensive to becommercially feasible.

It is also known that the pinene-derived acids can be produced byozonizing alpha-pinene and decomposing the ozonides into the acids.However, the ozonides of alpha-pinene are insoluble in alpha-pinene inturpentine and in hydrocarbons generally, and also in halo-hydrocarbonsgenerally. As is well known, undiluted ozonides are dangerous becausethey often become explosively reactive under ordinary conditions oftemperature and pressure. Therefore, while ozonization processes whichinvolve an ozonization of alpha-pinene in the vapor-phase, or in carbontetrachloride, or in hexane, or in chloroform, have been reported, suchprocesses inherently involve the production of considerable quantitiesof undiluted ozonides, a possibly dangerous material.

We have discovered that alpha-pinene can be converted to pinene-derivedacids by an ozonolysis process in which no undiluted ozonides areformed, if, in the process, the alpha-pinene is ozonized while mixedwith a liquid ozonolysis medium in which the ozonides of alpha-pineneare appreciably soluble. We have discovered that when anozone-containing gas is passed, in accordance with a con ventionalprocedure for the ozonization of a liquid, into a mixture of,alpha-pinene and such a medium at a temperature between the freezingtemperature of the solution of alpha-pinene in said medium and thetemperature at which ozonides of alpha-pinene dissolved in said mediumdecompose at an uncontrollably rapid rate, the ozonization reactionproduces ozonides of alpha-pinene dissolved in said medium rather thanproducing a separate phase consisting essentially of ozonides. We havediscovered that certain alkanols, alkanoic acids, nitroalkanes,alkanediols and mixtures thereof not only constitute liquid ozonolysismediums in which alpha-pinene can be so ozonized, but also constitutemediums in which the ozonides so produced can be decomposed into thepinenederived acids by a homogeneous liquid-phase reaction with anozonide-decomposing reagen We have discovered that certain liquids suchas acetic acid, nitromethane and liquid alkanol solutions containingdissolved aqueous alkali metal hydroxides not only constitute liquidozonolysis mediums in which alpha-pinene can be so ozonized but alsoconstitute ozonide-decomposing reagents in which the dissolved ozonidescan be caused to undergo decomposition into the pinene-derived acids ata controllable rate by raising the temperature of the solution. We havealso discovered that such a conversion of alphapinene can be controlledto favor the production of hydrocarbon dicarboxylic or keto-substitutedmonocarboxylic pinene-derive-d acids by dissolving in the liquid phasecontaining the ozonides, during or following the decomposition of theozonides with an oxonide-decomposing reagent, anozonidedecomposition-controlling reagent such as hydrogen peroxide,water-soluble inorganic peroxides, or a water-soluble mixture of saltsof the hypohalous acids with excess inorganic base.

The process of producing pinene-derived acids, provided by thisinvention, comprises: mixing alpha-pinene with a liquid ozonolysismedium; contacting the mixture with an ozone-containing gas; andsubjecting the dissolved ozonides so produced to an acid-producingozonide decomposition.

Throughout the remainder of the specification, and in the claims: theterm liquid ozonolysis medium refers to a material which is ahomogeneous liquid at atmospheric temperatures and pressures, whichconsists of one or a plurality of substances, Which is appreciablymiscible (miscible with at least 0.05 part by weight) with alpha-pineneand the ozonides of alpha-pinene, and which is substantially unreactivetowards ozone at a temperature between the temperature at which a solution of alpha-pineue in said material freezes and the temperature atwhich the ozonides of alpha-pinene dis solved in said material undergoan uncontrollably rapid decomposition; the term ozonide-decomposingreagent refers to a substance which is composed of one or morecompounds, which reacts with the ozonides of alphapinene to produce oneor more pinene-derived acids, which is sufliciently miscible with aliquid ozonolysis medium (at least in the presence of an unreactivemutual solvent) to so react with the ozo'nides in a homogeneous liquidphase containing the ozonides at a temperature between the freezingtemperature of the solution of ozonides in the liquid ozonolysis mediumand the tern perature at which the ozonides dissolved in the liquidozonolysis medium undergo a thermal decomposition; the term"ozonide-decomposition-controlling reagent" refers to a substance whichis composed of one or more compounds, which reacts with a portion of thedecomposing ozonides of alpha-pinene or with a portion of thepinene-derived acids to produce hydrocarbon dicarboxylic pinene-derivedacids or to produce keto-substituted monocarboxylic pinene-derived acidsbetween the temperatures at which a solution of alpha-pinene ozonides ina liquid ozonolysis medium freezes and boils under atmospheric pressure.

A preferred method of conducting the process of this inventioncomprises: mixing alpha-pinene with from 2 to parts of methanol;ozonizing the solution so produced at a temperature between the freezingtemperature of the solution and the uncontrollably rapid decompositiontemperature of the dissolved ozonides of alphapinene; and adding, to thesolution of ozonides so produced, an amount of sodium hypochloriteproviding at least an equivalent of hypochlorite anions based on theamount of ozonides in solution and an amount of sodium hydroxidesufiicient to render the solution basic, at a temperature of from to 125C.

A preferred method of conducting the process comprises: ozonizingalpha-pinene by the above preferred method in which the methanol isreplaced by acetic acid; and decomposing the ozonides by diluting thesolution of them, so produced, with from 0.1 to 2 parts of water, at atemperature of from 20 to 125 C.

A preferred method of conducting the process comprises: ozonizingalpha-pinene by the above preferred method using acetic acid; anddecomposing the ozonides by dissolving in the solution of them, soproduced, from 0.1 to 2 parts of Water and frorn 0.0l to 0.03 part ofhydrogen peroxide, at from 20 to 125 C.

Where the liquid ozonolysis medium used is completely miscible withalpha-pinene it is preferable to mix the pinene with about 2 to 10 partsof said medium prior to ozonization.

Where the liquid ozonolysis medium used is only partially miscible withalpha-pinene up to about 1 part of undissolved alpha-pinene for eachpart of liquid ozonolysis medium can suitably be present in the reactorat the start of the ozonization.

The miscibility of the ozonide-decomposing reagent and/or theozonide-decomposition-controlling reagent with the liquid ozonolysismedium can suitably vary widely, and mutual solvents to increase themiscibility of said reagents can suitably be added to the effluent fromthe ozonization reaction vessel. However, preferred liquid ozonizationmediums are those which will dissolve, per part by weight of ozonizationmedium, at least 0.1 part of alpha-pinene, at least 0.2 part of a-piueneozonide, at least 0.1 part of ozouide-decomposing reagent, and, if oneis to be used, at least 0.02 part of ozonide-decomposition-controllingreagent.

Illustrative examples of liquids which, individually or mixed together,can suitably constitute the liquid ozonization medium used in theprocess of this invention include: the normally liquid alkanols such asmethanol, ethanol, the butanols, the hexanols, the octanols, and thelike alcohols; nitromethane; ethylene, propylene, butylone and the likeglycols; the thermally stable watersoluble alkanoic acids, i. e. thosecontaining from 2 to about 5 carbon atoms, such as acetic, propionic,isobutyric and the like acids. Methanol and acetic acid are particularlysuitable.

Illustrative examples of liquids which, individually or mixed together,can suitably constitute both the liquid ozonolysis medium and theozonide-decomposing reagent, include: solutions consisting of alkalimetal hydroxides dissolved in homogeneous aqueous alkanols which solutions, in the amounts used, contain an amount of base sufiicient toneutralize the amount of pinene derived acids obtainable from the amountof alpha-pinene ozonized, e. g., from 0.3 to 1 part of sodium hydroxidein from 50% to aqueous methanol per part of alphapinene; nitromethane;and concentrated completely watermiscible alkanoic acids, e. g., aqueousacetice acids of from 50% to acetic acid. Such liquids can suitably beused as ozonolysis mediums for an ozonolysis conducted at a temperaturebelow the decomposition temperature of the dissolved ozonides andsubsequently used as ozonide decomposing reagents by causing thetemperature to increase until decomposition occurs. They can also besuitably used as mediums in which both the formation of the ozonide andthe acid-producing decomposition of the ozonide occurs concurrently byconducting the ozonization at some higher temperature bclow thetemperature at which the rate of decomposition of the dissolved ozonidesbecomes uncontrollably rapid.

Illustrative examples of: suitable ozonide-decomposing reagents,include: water-soluble organic acids such as the alkanoic acids of from2 to 5 carbon atoms, the inorganic strong acids such as nitric,hydrochloric, perchloric, sulfuric, phosphoric and the like acids, andthe water-soluble inorganic bases such as the hydroxides of the alkalimetals and the like bases. Acetic acid and sodium hydroxide areparticularly suitable. The ozonidedecomposing reagents are preferablyadded in increments in the form of an aqueous solution containing one ormore of "such reagents.

Illustrative examples of suitable ozonide-decomposition-controllingreagents, include: water-soluble inorganic peroxides such as hydrogenperoxide, sodium peroxide, sodium persulfate, and thelike peroxides;water-soluble salts of the hypohalous acids in conjunction with anexcess of base; and the alkali metal hypohalites in conjunction with anexcess of an alkali metal hydroxide. Hydrogen peroxide and basic aqueoussolutions of the alkali metal hypohalites are particularly suitable.

The ozonization of dissolved alpha-pinene, in accordance with theprocess of the present invention, can suitably be carried out inaccordance with any of the conartisan The process of the presentinvention can suitably be conducted in a batchwise or a continuousmanner. The preferred temperatures at which to conduct the ozonizationin accordance with the process of this invention range from about to +30C. The preferred temperatures at which to decompose the ozonides so produced range from about 20 to 125 C.

The mixtures of pinene-derived acids provided by the present inventioncan be isolated by various separation procedures. For example, theunreacted pinene and/or the solvent can be extracted from the salts ofthe acids produced by decomposing the ozonides in a basic medium, and,after the salts are neutralized, the acids can be separated byextraction followed by fractional distillation. Where a hydroxy compoundis used as the solvent, the acids can conveniently be esterified in situand then the resulting esters can be separated by fractionaldistillation. The use of hexanol as the solvent and the separation ofthe acids by an esterification in situ followed by fractionaldistillation of the hexyl esters of the acids is a preferred method ofproducing and separating the pinene-derived acids in accordance with thepresent process. The esters so separated can, of course, be converted tothe free acids by conventional ester cleavage reactions. And, of course,in the production of a mixture of esters provided by this invention,where the esters desired are those of an alcohol meeting thequalifications of the liquid ozonization medium, it is preferable toemploy the alcohol as said medium and to form the esters in situ.

Unique and valuable mixtures of pinene-derived acids of two differentgroups composed of acids of closely related chemical and physicalproperties are provided by this invention.

The mixtures of the first of such groups consist of mixtures ofpinene-derived acids composed substantially entirely of hydrocarbondicarboxylic acids and predominating in pinic and norpinic acids, i. e.mixtures of acids all of which are pinene-derived acids which mixturescontain only trace amounts of acids having a structure other than thatof the pinic and norpinic acids. One preferred group of such acidsconsists of a mixture of pinene-derived acids boiling between about 170to 190 C. under a pressure supporting 0.5 mm. of mercury, having arefractive index (n between about 1.475 to 1.485, and containing atleast 80% pinic acids. Another preferred group of such acids consists ofa mixture of pinene-derived acids that form a mixture of neutral hexylesters boiling between about 140 to 170 C. under a pressure supporting0.05 mm. of mercury, having a refractive index (n between about 1.450 to1.455, and containing at least 80% dihexyl pinates.

The mixtures of the second of such groups consist of mixtures ofpinene-derived acids composed substantially entirely of keto-substitutedmonocarboxylic acids and predominating in pinonic and pinononic acids.One preferred group of such acids consists of a mixture ofpinene-derived acids boiling between about 140 to 160 C. under apressure supporting 0.5 mm. of mercury, having a refractive index (nbetween about 1.465 to 1.475, and containing at least 80% pinonic acids.Another preferred group of such acids consists of a mixture ofpinene-derived acids that form a mixture of neutral hexyl esters boilingbetween about 120 to 140 C; under a pressure supporting 0.05 mm. ofmercury, having a refractive index (n between about 1.455 to 1.460, andcontaining at least 80% hexyl pinonates.

The mixtures of keto-substituted monocarboxylic pinene-derived acidswhich are primarily composed of pinonic acid and pinononic acid provide(by virtue of 6 their esterification reactions, and the propertiesimparted to the products of such reactions by the presence of the acylradicals contained in them), mixtures which constitute valuableplasticizers when esterified with glycols such as ethylene anddiethylene glycol, propylene glycol, butane-1,4-diol and the like.

The following examples are presented to illustrate in more detailcertain features involved in the practice of this invention.

Example I Use of a liquid ozonolysis medium which is also anozonide-decomposing reagent.Fifty ml. of alpha-pinene (0.31 moles) mixedwith 150 ml. of acetic acid was ozonized at about 30 C. About 0.2 molesof ozonide was obtained. The acetic acid solution was diluted with anequal volume of water and heated at about C. for 3 hours and the waterand acetic acid were then removed in vacuo. 26.6 g. of semisolid productcontaining 0.1 equivalent of acid was obtained. Crystallization fromether and then from water gave 6.9 g. of acids, neutral equivalent=200,M. P. 89 to 91 C. From this mixture of acids pinonic acid, M. P. 103 C.,neutral equivalent 185 was obtained by crystallization from benzene. Amixture of this acid with an authentic sample of pinonic acid (meltingpoint C.) melted at 104 to 105 C.

Example 11 Use of an ozonolysis medium incompletely miscible with theamount 0 alpha-pinene used.-Fifty ml. (0.31 moles) of alpha-pinene wasmixed with a mixture of 50 ml. of acetic acid and 50 ml. of water. Partof the alphapinene was not dissolved. This suspension was ozonized at 0to 10 C. 0.2 moles of ozone was absorbed and the resultant solutioncontained 0.2 moles of ozonide. All the ozonide remained in solution.This acid solution of ozonide was refluxed for 1 hour, which treatmentdecomposed 80 percent of the ozonide. Removal of the solvents bydistillation gave 36 g. of semisolid product containing 0.07 equivalentof acids.

Example 111 Use 0 an ozonide-decomposition-c0ntrolling reagent daringdecomposition-0.31 moles of alpha-pinene mixed with 100 ml. of 50percent aqueous acetic acid was ozonized at room temperature (about 30C.). 0.1 mole of ozone was absorbed and 0.1 mole of ozonide was presentin the resulting solution. Substantial amounts of alpha-pinene were lostfrom the reactor by vaporization and entrainment but were recoverablewith a suitable scrubbing system.

The resultant solution was divided in two equal parts. One part wasrefluxed for 1.5 hours at about 100 C. and the solvent was then removedby distillation at below C. using vacuum as required. 8.5 g. ofsemisolid product containing 0.038 equivalent of acids was obtained.Analysis of the product by the method of Marvel and Rands (J. Am. Chem.Soc. 72, 2642 (1950) indicated that it contained 0.018 moles of pinonicacid.

The second part was adjusted to 3 percent hydrogen peroxide content byaddition of 30 percent hydrogen peroxide and then treated in the sameway as the first part. 9.4 g. of semisolid product containing 0.045equivalent of acids of which 0.028 moles were pinonic acids wasobtained.

Example IV Use of an ozonide-decomposition-cohtr0lling reagent afterdecomposition-0.31 moles of alpha-pinene mixed with ml. of acetic acidwas ozonized at 0 to 10 C. 0.21 moles of ozone was absorbed and an equalamount of ozonide was present in the resultant solution. Decompositionby refluxing at about 115 C. in the presence of 3 percent of hydrogenperoxide and removal of the solvent gave 44 g. of product containing0.17 equivalent of acids. This product was then refluxed for 2 hourswith 50 ml. of 3 percent hydrogen peroxide and the solvent was againremoved. 39 g. of product containing 0.17 equivalent of acids wasobtained. Analysis of this product by the method of Marvel and Randsindicated the presence of 0.07 moles of pinonic acid and 0.035 moles ofpinic acid.

Example V Use of anozonolysis medium miscible with theozonidcdecomposing and ozonide-rlecomposition-controlling reagent-0.31moles of alpha-pinene was mixed with 150 ml. of methanol and ozonized atto 10 C. The resultant solution contained 0.28 moles of ozonide.Dropwise addition of 600 ml. of a 6 N aqueous sodium hypochloridesolution, containing 0.3 moles of excess sodium hydroxide, to the abovesolution, with vigorous stirring gave an exothermic reaction. Rate ofaddition was adjusted to maintain a temperature of 40 to 50 C. When allhad been added (about hours) the mixture was heated to 70 C. for 1 hour.

After evaporation of the methanol and extraction with chloroform toremove any neutrals, the basic aqueous phase was acidified with sulfuricacid and the acid prod ucts were isolated by extraction with chloroform.The chloroform solution was washed and dried and the solvent was thenremoved. About 20 g. of product, neutral equivalent 126, was obtained.Analysis by the method of Marvel and Rands indicates about 5 g. ofpinonic acids and about g. of hydrocarbon dicarboxylic acids includingpinic acids.

Example VI Analogous to Example V with differentozonide-dec0mposition-c0ntr0lling reagent.-A solution of ozonideprepared in the manner described in Example V and containing 0.25 molesof ozonide was divided into three equal portions for decomposition.

0.08 moles of 5 N sodium hydroxide was added dropwise to one portion.The temperature rose to about 65 C. and was maintained by a suitablerate of addition of base. This addition required 40 minutes and theozonide was substantially all decomposed. Neutrals were removed and theacids isolated as in Example V. 4.4 g. of acids, neutral equivalent=205was obtained. The Marvel and Rands analysis indicated 2.7 g. of pinonicacids and 0.2 g. of pinic acids. The second portion was treated with0.08 moles of base and 0.08 moles of hydrogen peroxide in the samemanner as the first portion, and the product was recovered in the sameway. 5.0 g. of acids, neutral equivalent=226 was obtained. The Marveland Rands analysis indicated 2.9 g. of pinonic acids and 0.3 g. of pinicacids. The third portion was treated with 0.08 moles of hydrogenperoxide. There was no evidence of reaction so the solution was heatedat 75 C. for 3 hours. At the end of this time the ozonidc and peroxidecontent of the solution had not changed. Hence, 10 percent by volume ofnitric acid (1:4) was added and the heating was continued for 4 hours.Over 95 percent of the ori inal active oxygen content of the solutionwas decomposed. Evaporation under vacuum yielded a product containing0.01 equivalent of acids.

Example VII Ozonizrztion and concurrent decomposition in an 07,0-nolysis medium which is also a ozonl'a'e decomposing reagent-0.5 molesof alpha-pinene and 0.5 moles of sodium hydroxide mixed with 140 ml. ofmethanol were ozonized at about 10 C. 0.48 moles of ozone was absorbedout no ozonide was present in the resulting solution and only 0.18equivalent of free base remained. This solution was diluted with anequal volume of water and the neutrals were extracted with ether. Thebasic solution was then acidified and the acids were extracted withether and isolated by removal of the solvent. 32 g. of productcontaining 0.08 equivalent of acid was obtained.

Marvel and Brands analysis indicates 0.061 moles of pinonic acids and0.005 moles of pinic acids.

7 Example VIII Use of alcohol to be esterified as ozonization medium,esterification in situ and isolation of mixtures of esters.- 50 ml.(0.31 moles) of alpha-pinene was mixed with ml. of hexanol and ozonizedat 0 to 10 C. using 020- nized oxygen containing about 1 percent ozone.A clear solution containing 0.24 moles of ozonide was obtained. A totalof 800 ml. of sodium hypochlorite solution (12%) was added slowly to thewell-stirred ozonide solution, the rate of addition being adjusted tomaintain a temperature of 40i5 C. When the reaction was complete themixture was acidified with sulfuric acid and the hexanol layer wasseparated. The pinene-derived acids remaining in the aqueous phase wererecovered by other extraction and added to the hexanol layer. About 0.3equivalent of acids were obtained. Toluene (150 m1.) and sulfuric acid(3 ml. of 50%) were added and the mixture was refluxed for 2.5 hours toesterify the acids. Residual acid was removed by Washing the solutionwith 40 ml. of l N base followed by two water washes. After removal ofthe toluene and hexanol about 60 g. of product was obtained. This wasdistilled at about 0.2 mm. to give the following cuts. Cut 1, to C. 12g. n =l.458; cut 2, 19 g. 145 to 165 C. n =l.453. Cut 1 predominates inhexyl pinonates free from dicarboxylic esters and cut 2 predominates indihexyl pinates free from mono carboxylic esters.

Example IX Analogous to Example III but with a different ozonolysisnzeclium.--l00 g. of a solution of alpha-pinene ozonide in nitromethanecontaining 0.062 moles of the ozonide, prepared by ozonization ofalpha-pinene mixed with three parts of nitromethane, substantially inthe main not described in Example ill was refluxed several hours todecompose the ozonide. Removal of the nitromethane in vacuo gave 16.3 g.of product containing 0.026 equivalent of acid. Of this, 0.021equivalent was found to be pinonic acids by the Marvel and Randsanalysis.

To a second 100 g. portion of the same ozonide solution (0.062 moles ofozonide) 11 g. of 30 percent hydrogen peroxide was added and the mixturewas refluxed for several hours until both ozonide and hydrogen peroxidewere decomposedv After removal of solvent in vacuo 18.7 g. of productcontaining 0.054 equivalent of acid was obtained. Of this 0.039equivalent of pinonic acids and 0.007 equivalent of pinic acids werefound by Marvel and Rands analysis.

Example X to XIII Unique plasticizer properties of esters 0 the mixtureso t acids provided by this inven i0n.-A mixture of pinencderived acidspredominating in the pinic acids was esterified, by a conventionalesterification procedure, with n-hexanol. The mixture of esters soproduced was subjected to fractional distillation isolating a mixture ofneutral n-hexyl esters boiling between about 140 and C. under a pressuresupporting 0.05 to 0.1 mm. of mercury, having a refractive index (nbetween about 1.452 and 1.453, and containing at least 90% esterifiedpinic acid. Analogous mixtures of butyl celiosolve, n-arnyl alcohol andn-octyl alcohol esters were prepared in an analogous manner.

A series of esters were incorporated to the extent of 35 or 40% in acommercially available inyl resin (using Vinylite VYDR). Thecompositions so obtained were tested for tensile strength and elongation(using an IP4 machine) at a loading rate of 200 pounds per minute at 70F. with a relative humidity of 65:292. The compositions were alsosubjected to a brittle test, basically that described as A. S. T. M.test D746-43T.

The values obtained are reported in the following table. Thoseobtainedfrom the various mixtures of esters described above are designatedsimply as the various alkyl esters numbers X to XIII. The valuesobtained from two commercially available di-octyl esters are reportedfor comparison.

Modulus 100% Ultimate Brittle Iensrle, elon elonga- Point p. s. i. 5tion, a C

p S i percent Compositions Containing 35% er: X. 2-butoxyethyl ester 2,794 1, 252 316 45 XI. Di-n-amyl ester: 2, 758 1, 260 331 44 XII.Di-n-hexyl ester. 2, 742 1, 329 297 -49 XIII. Di-n-octyl ester 2, 675 1,492 324 54 Dioetyl phthala 3, 040 1, 550 330 33 Dioctyl sebaeate 2, 5191, 406 308 58 Contpositions Containing 40% es er:

XIII. Di-n-octyl ester 2, 285 1, 178 354 71 Dioetyl sebaeate 2, 176 874350 -69 The above plasticized resin compositions were milled and moldedat 300 F. and in each case the esters of the mixed pinene-derived acidsproduced a white or light cream colored sheet.

Those skilled in the art will recognize that the above tests demonstratethat unique and valuable properties are imparted to the above esters bythe acyl radicals contained in the mixture of acids from which theesters were formed. In each of the properties tested the esters of thepinenederived acids proved to be substantially equal to or better thanthe commonly employed commercially available plasticizers with whichthey were compared. The esters of the cyclic acids heretofore known (ofindividual acids or of mixtures of acids) have been characterized bytheir relative inefficiency as plasticizers. The discovery that thesemixtures of esters of saturated cyclic acids plasticize a resincomposition with approximately the same eificiency as do thecorresponding esters of sebacic acid is a particularly unobviousvaluable discovery in the field of resin chemistry.

Having thus described our invention we claim:

1. A process of ozonizing alpha-pinene to produce pinene-derived acids,comprising mixing alpha-pinene and methanol in proportion of one partalpha-pinene to about from 2 to parts of methanol; contacting themixture with an ozone containing gas; and subjecting the dissolvedozonides so produced to an acid producing decomposi tion by mixing withthe solution containing them at least an equivalent amount of sodiumhypochlorite and sufiicient sodium hydroxide to make the mixture basicat about from 20 to 125 C.

2. A process of ozonizing alpha-pinene to produce pinene-derived acids,comprising mixing alpha-pinene and acetic acid in proportion of one partalpha-pinene to about from 2 to 10 parts of the acetic acid; contactingthe mixture with an ozone containing gas; and subjecting the dissolvedozonides so produced to an acid producing decomposition by mixing withthe solution containing them about from 0.1 to 2 parts of water at aboutfrom 20 to C.

3. A process of ozonizing alpha-pinene to produce pinene-derived acids,comprising mixing alpha-pinene and an unreactive liquid ozonolysismedium selected from the group consisting of alkanols, alkanoic acid,and nitroparaflins which are appreciably miscible with both alphapineneand the ozonide of alpha-pinene; contacting the mixture with anozone-containing gas; and subjecting the dissolved ozonides so producedto an acid producing decomposition by mixing with the solutioncontaining them about from 0.1 to 2 parts of water and about from 0.01to 0.03 part of hydrogen peroxide at about from 20 to 125 C.

4. The process of claim 3 in which the liquid ozonolysis medium isacetic acid and in which the alpha-pinene and acetic acid are inproportion of one part alpha-pinene to about from 2 to 10 parts ofacetic acid.

References Cited in the file of this patent UNITED STATES PATENTS1,924,805 Rogers Aug. 29, 1933 2,232,933 Wiley Feb. 25, 1941 2,560,242Pelton et al. July 10, 1951 OTHER REFERENCES Tiemann: Ber. Deut. Chem.,vol. 33, page 2664 (1900).

Harries et al.: Ber. Deut. Chem., vol. 41, pgs. 38-42 (1908).

Harries et al.: Ber. Deut. Chem., vol. 42, pgs. 879-880 (1909).

Harries et al.: Chem. Abstracts, vol. 4, pg. 2488 (1910).

3. A PROCESS OF OZONIZING ALPHA-PINENE TO PRODUCE PINENE-DERIVED ACIDS,COMPRISING MIXING ALPHA-PINENE AND AN UNREACTIVE LIQUID OZONOLYSISMEDIUM SELECTED FROM THE GROUP CONSISTING OF ALKANOLS, ALKANOIC ACID,AND NITROPARAFFINS WHICH ARE APPRECIABLY MISCIBLE WITH BOTH ALPHAPINENEAND THE OZONIDE OF ALPHA-PINENE; CONTACTING THE MIXTURE WITH ANOZONE-CONTAINING GAS; AND SUBJECTING THE DISSOLVED OZONIDES SO PRODUCEDTO AN ACID PRODUCING DECOMPOSITION BY MIXING WITH THE SOLUTIONCONTAINING THEM ABOUT FROM 0.1 TO 2 PARTS OF WATER AND ABOUT FROM 0.01TO 0.03 PART OF HYDROGEN PEROXIDE AT ABOUT FROM 20* TO 125* C.